1. Field of the Invention
This invention relates to an endoscope having a solid-state image pickup device in its distal end portion.
2. Description of Related Art
In recent years, wide use has been made of endoscopes which have elongated insert portions to be inserted into body cavities to observe internal organs, and treating instrument channels into which treating instruments are inserted to perform various treating operations. Also use has been made of electronic endoscopes which have solid-state image pickup devices, such as CCDs, in the distal end portions of the insert portions.
As shown in FIG. 1, an electronic endoscope is provided in the distal end portion 7 of the insert portion with an image pickup portion 30 comprising an objective optical system 43 and an image pickup unit including a solid-state image pickup device 48 and its peripheral circuitry. Conventionally, signal lines 32 connected to the image pickup unit of the solid-state image pickup portion 30 have been arranged in the peripheral area of the distal end portion 7 from a standpoint of layout and extended from the rear end of the image pickup portion 30 into a bending portion 8 vertically, that is, in parallel with the axis of the insert portion.
However, the bending portion 8 of the insert portion includes in its peripheral area a wire 17 for bending operation, a wire guide 15 for fixing the distal end of the wire 17, and a wire receiver 18 through which the wire 17 extends. Since the signal lines 32 have long rigid portions extended from the rear end of the image pickup portion 30, there is a fear that the wire guide 15, the wire receiver 18, the wire 17, etc., will interfere with the signal lines 32 when the bending portion 8 is bent. This interference may break the signal lines 32 or affect the bending operation 8.
Therefore, conventionally the bending portion 8 has had to be thick in order to prevent the wire guide 15, the wire receiver 18, the wire 17, etc., from interfering with the signal lines 32.